Norovirus VLPs and rotavirus VP6 protein as combined vaccine for childhood gastroenteritis.

Noroviruses (NoVs) and rotaviruses (RVs) are the two most important viral causes of severe gastroenteritis in young children worldwide. Live oral RV vaccines are already part of routine childhood immunization in many countries, but may be associated with low risk of intussusception and other potential risks associated with live vaccines. NoV capsid-derived virus-like particles (VLPs) are in early phase clinical trials, but there is no vaccine available yet. We suggest that there is a need for non-live vaccines against both enteric pathogens. We have combined NoV GII-4 VLPs and human RV recombinant VP6 (rVP6) protein produced by recombinant baculovirus (BV) expression system in insect cells and used this combination vaccine to immunize BALB/c mice parenterally. Strong systemic cross-reactive and cross-blocking antibody responses towards NoV and RV were induced, and there was no interference of the immune response to either antigen given in combination. Rather, we observed an adjuvant effect of rVP6 on the NoV-specific homologous and heterologous immune responses to genotypes not included in a vaccine formulation.